The present invention relates to a head strap for headphones or hearing protectors with two ear members connected by two almost parallel wire arcs that are held together by a connecting member.
The head strap of a set of headphones or hearing protectors has to hold both ear members together such that, when the headphones are positioned on the head of a user, the head strap applies a certain minimum spring tension by which the ear members are pressed towards the ears. Head straps of plastic material do not provide constant spring forcesxe2x80x94especially when humidity is involved. In particular with closed headphones and hearing protectors, however, a constant contact pressure is imperative for a good functionality. Head straps have proven suited, in particular with closed headphones and hearing protectors, which are formed by two generally parallel wire arcs for connecting both ear members. The two wire arcs are held together by a connecting member designed as a head cushion. The head cushion is a soft pad into which sections of the two wire arcs are welded. Since both wire arcs can move relative to each other and within the head cushion, the head strap only has limited stability and rigidity. Thus, the flexible connecting member is worn down fast and possibly torn. The flexible connecting member is preferably made by HF welding two plastic films between which the wire arcs are located.
It is the object of the present invention to provide a more stable head strap for headphones or hearing protectors.
The connecting member of the present invention is designed as a rigid plate comprising two recesses extending longitudinally over the entire length of the plate, a respective wire arc section being fixed therein. Thus, the plate forms a rigid bridge between the two wire arcs so that the relative movability of the two wire arcs is reduced to a minimum. By reducing the movability and selecting a-more robust material for the connecting member, the durability of the head strap is improved considerably. The wire arc section in the recess can no longer be overstretched so that, all in all, the spring force and thus the contact pressure are maintained. The rigid plate is a single piece member, for example, and is easily assembled with the wire arcs to form a head strap.
Preferably, the recesses are provided at the longitudinal edges of the plate. Thus, almost the entire width of the plate lies between the two wire arcs.
According to a preferred embodiment, the recess is formed step-like so that the wire arcs may readily be set into the recess. Alternatively, the recess may also be a gap into which the wire arc section may be clamped. In this manner, a firm connection is created already when assembling the wire arcs and the plate. Preferably, the wire arc sections are each cast in plastic within the recesses. After the wire arcs have been placed into the recess of the pre-fabricated rigid plate, the opening of the recess is filled with plastic material. This may also be a soft elastic plastic material, for example, in order to guarantee a minimum movability of the wire arc section in the recess. By casting the wire arc sections in plastic in the recesses, a permanent and firm connection between the wire arc and the rigid plate is obtained that guarantees a long serviceable life of the head strap.
According to a preferred embodiment, at least two rigid plates are provided for holding the wire arcs together. When several plates are used, a certain flexibility of the wire arcs remains between the plates. In this manner, a great rigidity and a high stability of the head strap are achieved without degrading of the resilient and tensioning properties of the wire arcs too much.
Preferably, a joint of elastic plastic material is permanently molded between two adjacent plates. One may also provide a bellows or the like as a joint between two adjacent plates. Hereby, it is primarily guaranteed that the space between two plates is filled or closed so that the space between two plates is mostly free of edges gaps and steps. Thus, deposits in this area are avoided and the head strap is easier to clean. The joint may also be a film hinge.
Preferably, the plate has a longitudinally extending wire channel. The wire channel may be provided in the center between the two recesses. In particular with head straps for headphones, the cable channel may accommodate cables for transmitting audio signals or control signals.
According to another preferred embodiment, the plate has longitudinally extending opposite grooves into which lateral webs of a padding element may be inserted. In this manner, the padding element is easy to assemble and also replaceable.